似單氧化酵素之三核錳金屬簇化物之研究

Abstract

本實驗室先前的研究中，我們發展出7-Dipy配位基成功合成出三核錳金屬簇離子化合物 [MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) ，作為高價態的錳金屬簇離子化合物的前驅物，藉由加入二當量氧化劑TBHP氧化[MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) ，可得一組16根特徵吸收之ERP光譜，在此假定得到一活性中間體[MnIIIMnIII(μ-O)2MnIV(7-Dipy)]4+ (4)，在催化上，可藉由加入氧化劑TBHP可將環己烷氧化為環己醇與環己酮。 在我的研究中，將受質嘗試使用其他環烷類與長鏈烷類，包含 環戊烷、正戊烷、正己烷、正庚烷與正辛烷，皆能進行催化生成多碳位氧化的醇類及酮類。 為了解三核錳金屬簇離子化合物[MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] 催化反應，是自由基反應或是經由單氧直接嵌入的一步反應機構，我們利用DMPO對自由基物質相當靈敏的特性，將三核錳金屬簇化物加入DMPO進行實驗，由實驗的EPR光譜可以得到，我們推測三核錳金屬簇化物[MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] ，以甲醇為溶劑，加入TBHP進行催化反應立即所測知ERP光譜與DMPO=O之ERP光譜類似。

Previous studies in our laboratory, we developed a 7-Dipy ligand base successfully synthesized of trinuclear manganese complex. This trinuclear manganese complex [MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) was synthexized as a precursor for the high-valent manganese species. Further oxidation of [MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) by treating two equivalents of TBHP (tert-butyl hydroperoxide) is able to obtain a 16-line characteristic EPR spectrum, which is postulated as a active intermediate, [MnIIIMnIII(μ-O)2MnIV(7-Dipy)]4+ (4)is able to catalyze the oxidation of C-H bonds of cyclohexane to a mixture of cyclohexanol and cyclohexanone. In my study, a series of substrates, other cycloalkane and long-chain alkanes, including cyclopentane, n-pentane, n-hexane, n-heptane and n-octane, are able to be oxidized. To further understand the trinuclear manganese complex [MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) carrying out catalytic raction are free radical reaction mechanism or via a single oxygen step reaxtion mechanism. Therefore, we designed a series of experiments using very sensitive to free radicals, DMPO to detect the trinuclear manganese complex [MnII(OAc)2MnII(μ-OAc)2MnII(7-Dipy)] (3) by adding TBHP catalytic reaction immediately by detect ERP spectra, which shows a NO. radical species and is similar to the DMPO  O of the ERP spectrum similar.